CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Pension and other post retirement obligations:
Amortization of actuarial losses included in net periodic pension cost, gross	$ 376	$ 363	$ 1,127	$ 1,090
Tax effect	(144)	(140)	(432)	(421)
Amortization of actuarial losses included in net periodic pension cost, net	232	223	695	669
Amortization of prior service cost included in net periodic pension cost, gross	(34)	(43)	(101)	(127)
Tax effect	13	16	39	49
Amortization of prior service cost included in net periodic pension cost, net	(21)	(27)	(62)	(78)
Other comprehensive income related to pension and other post retirement obligations, net of taxes	211	196	633	591
Unrealized gains/(losses) on available-for-sale securities:
Net unrealized holding (losses)/gains arising during period, gross	(24,465)	44,019	74,332	25,819
Tax effect	9,310	(16,979)	(28,109)	(11,223)
Net unrealized holding (losses)/gains arising during period, net	(15,155)	27,040	46,223	14,596
Other comprehensive (loss)/income related to unrealized (losses)/gains on available-for-sale securities, net of taxes	(15,155)	27,040	46,223	14,596
Other comprehensive (loss)/income, net of tax	(14,944)	27,236	46,856	15,187
Net income	27,160	25,022	77,420	71,159
Comprehensive income	12,216	$ 52,258	124,276	$ 86,346
Accumulated Other Comprehensive Income By Component:
Unrealized loss for pension and other post-retirement obligations	(33,321)		(33,321)		$ (34,347)
Tax effect	12,671		12,671		13,064
Net unrealized loss for pension and other post-retirement obligations	(20,650)		(20,650)		(21,283)
Unrealized gain on available-for-sale securities	140,167		140,167		65,835
Tax effect	(53,426)		(53,426)		(25,317)
Net unrealized gain on available-for-sale securities	86,741		86,741		40,518
Accumulated other comprehensive income	$ 66,091		$ 66,091		$ 19,235